AU2005259160A1 - Light pulse amplification in long optical fibers - Google Patents
Light pulse amplification in long optical fibers Download PDFInfo
- Publication number
- AU2005259160A1 AU2005259160A1 AU2005259160A AU2005259160A AU2005259160A1 AU 2005259160 A1 AU2005259160 A1 AU 2005259160A1 AU 2005259160 A AU2005259160 A AU 2005259160A AU 2005259160 A AU2005259160 A AU 2005259160A AU 2005259160 A1 AU2005259160 A1 AU 2005259160A1
- Authority
- AU
- Australia
- Prior art keywords
- light pulse
- fiber
- pump signal
- raman pump
- raman
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 239000013307 optical fiber Substances 0.000 title claims description 23
- 230000003321 amplification Effects 0.000 title claims description 16
- 238000003199 nucleic acid amplification method Methods 0.000 title claims description 16
- 238000001069 Raman spectroscopy Methods 0.000 claims description 64
- 239000000835 fiber Substances 0.000 claims description 42
- 238000000034 method Methods 0.000 claims description 16
- 238000000253 optical time-domain reflectometry Methods 0.000 claims description 7
- 239000006185 dispersion Substances 0.000 claims description 6
- 230000003287 optical effect Effects 0.000 claims description 6
- 238000005086 pumping Methods 0.000 claims description 3
- 230000001186 cumulative effect Effects 0.000 claims description 2
- 238000001514 detection method Methods 0.000 claims description 2
- 230000002238 attenuated effect Effects 0.000 description 4
- 230000003247 decreasing effect Effects 0.000 description 2
- 230000003111 delayed effect Effects 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 101150007711 rps5 gene Proteins 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/29—Repeaters
- H04B10/291—Repeaters in which processing or amplification is carried out without conversion of the main signal from optical form
- H04B10/2912—Repeaters in which processing or amplification is carried out without conversion of the main signal from optical form characterised by the medium used for amplification or processing
- H04B10/2916—Repeaters in which processing or amplification is carried out without conversion of the main signal from optical form characterised by the medium used for amplification or processing using Raman or Brillouin amplifiers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/30—Testing of optical devices, constituted by fibre optics or optical waveguides
- G01M11/31—Testing of optical devices, constituted by fibre optics or optical waveguides with a light emitter and a light receiver being disposed at the same side of a fibre or waveguide end-face, e.g. reflectometers
- G01M11/319—Reflectometers using stimulated back-scatter, e.g. Raman or fibre amplifiers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
- H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
- H01S3/094003—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light the pumped medium being a fibre
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/30—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects
- H01S3/302—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects in an optical fibre
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- General Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
- Lasers (AREA)
Description
WO 2006/003206 PCT/EP2005/053218 LIGHT PULSE AMPLIFICATION IN LONG OPTICAL FIBERS BACKGROUND OF THE INVENTION The invention relates to a method and system for amplifying a light pulse in an optical fiber. If light pulses are transmitted through long optical 5 fibers the strength of the light pulses is gradually decreased due to reflection, scattering and/or absorption of the photons that are emitted through the optical fiber and reflected by a reflective coating surrounding the optical fiber. 10 International patent application WO 02/13423 discloses a method for amplification of the attenuated signal by means of multiple amplification signals, which are generally known as a Raman pump signals. The known amplification method is generally known as Raman pumping 15 and employs a pump signal that has a lower wavelength than the attenuated light pulse and is transmitted simultaneously and continuously with the signal light pulses into the fiber, such that the pump signals) interacts with the attenuated light pulses over a length 20 of fiber, which may be between one and several hundreds of kilometres, and stimulated Raman scattering amplify the attenuated signal. International patent application WO 00/65698 discloses a wide bandwidth Raman amplifier wherein at 25 least three pump sources provide pump power at different pump wavelengths that are spaced apart from another such that a prescribed Raman gain profile is generated in the optical fiber portion.
WO 2006/003206 PCT/EP2005/053218 -2 International patent application WO 02/084819 discloses an optical amplification system employing multiple laser groupings to provide a desired, e.g. flat, gain profile over a selected range of optical signal 5 wavelengths. The article "Extended-range optical time domain reflectometry (ODTR) system at 1650 nm based on delayed Raman amplification" published by Kee et al. in the magazine Optics Letters, Vol.23, No.5, 1 March 1998 10 discloses a delayed Raman amplification of a 1650 nm signal pulse by a 1530 nm pump pulse, such that amplification occurs when the two pulses overlap, and the position where amplification occurs is determined by the initial delay between the pulses and the fiber 15 dispersion. The currently available Optical Time Domain Reflectometry based sensing techniques are limited in output power of the emitted light pulse due to Stimulated Brillouin Scattering (SBS) in the optical fiber. If a 20 pump or signal light exceeds a certain power level in the fiber, the density of the fiber changes, which triggers SBS whereby most of the light bounces back to the direction it came form. The SBS effect limits the maximum range of the known sensing systems. 25 It is an object of the present invention to provide a Raman amplification method in which these limitations are alleviated. It is a further object of the present invention to extend the range of a pulsed sensing system by Raman 30 amplification in an optical fiber by amplifying/ compensating remotely for fiber losses when the signal level has decreased such that SBS is mitigated.
WO 2006/003206 PCT/EP2005/053218 -3 SUMMARY OF THE INVENTION Tn accordance with the invention there is provided a method for amplifying a light pulse in an optical fiber, wherein a Raman pump signal having a lower wavelength 5 than the light pulse is transmitted at a selected interval of time after the light pulse into the optical fiber, with dispersion such that the Raman pump signal travels faster through the fiber than the light pulse and reaches and enhances the light pulse after the light 10 pulse has travelled along a selected distance through the fiber, wherein the Raman pump signal is ramped in a substantially linear manner such that the amplification increases with the distance along which the light pulse has travelled along the length of the fiber and such that 15 the Raman gain is substantially similar to the fiber losses of the amplified signal. When used in this specification and accompanying claims the term dispersion indicates that the speed of light in a fiber is different for different wavelengths. 20 The term dispersion is also known as material dispersion and is a result of the physical effect that the index of refraction of a fiber core is different for different wavelengths, so that different spectral components (wavelengths) will propagate at different speeds along 25 the length of the fiber. The wavelength of the Raman pump signal may be between 50 and 250 nm lower than the wavelength of the light pulse and the wavelength of the light pulse may be between 1400 and 1700 nm and the Raman pump signal(RPS) 30 increases in a substantially linear manner from Al= SI+RPSmin at a distance dl to A 2 =S+ RPSmax at a distance d 2 >d 1 from the point where the light pulse is transmitted into the optical fiber.
WO 2006/003206 PCT/EP2005/053218 -4 The Raman pump signal may be transmitted at such an interval of time after the light pulse and may have such a lower wavelength than the light pulse that the Raman pump signal reaches the light pulse at a point in the 5 optical fiber which is located at a distance between 1 and 10 Kilometers from the point where the light pulse and Raman pump signal have been transmitted into the optical fiber. The Raman pump signal may be ramped such that full 10 gain of the light pulse by the Raman pump signal is accomplished at a distance of between 1 and 100 Kilometers from the point where the Raman pump signal has reached the light pulse. Optionally, the Raman pump signal contains multiple 15 Raman pumping wavelengths and is used to amplify both the light pulse and the part of the Raman pump signal that amplify the light pulse as they propagate down the fiber. In such case the different wavelengths of the Raman pump signal travel at different speed and overlap at different 20 times/locations. In such case it is preferred that the spacing between the different pump sources is from 30nm to 200nm. The system according to the invention for amplifying a light pulse in an optical fiber comprises a Raman pump 25 signal transmitter for transmitting a Raman pump signal having a lower wavelength than the light pulse at a selected interval of time after the light pulse into the optical fiber, such that the Raman pump signal travels faster through the fiber than the light pulse and reaches 30 and enhances the light pulse after the light pulse has travelled along a selected distance through the fiber, wherein the Raman pump signal is ramped such that the cumulative amplification increases with the distance WO 2006/003206 PCT/EP2005/053218 -5 along which the light pulse has travelled along the length of the fiber. Optionally, the system is configured for use to extend the reach of pulsed systems where the travel time 5 reflects position along a fiber. The pulsed system may be a pulsed sensing system, such as an Optical Time Domain Reflectometry (ODTR) system based on Rayleigh backscattering, a Strain and/or Temperature sensing system based on Brillouin 10 backscattering, a temperature sensing system based on Raman backscattering, an interferometric Fabry-Perot type sensing system, and/or a direct wavelength detection system based on Fiber Bragg Gratings (FBGs). These and other features, embodiments and advantages 15 of the method and system according to the invention will be apparent from the accompanying claims, abstract and the following detailed description of a preferred embodiment of the method and system according to the invention in which reference is made to the accompanying 20 drawing. BRIEF DESCRIPTION OF THE DRAWING FIG. 1 schematically illustrates an optical fiber through which a light pulse and a ramped Raman pump signal are transmitted such that the light pulse is 25 amplified in a gradually increasing manner as it travels along the length of the fiber. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT FIG.1 schematically illustrates an optical fiber 1 through which a pulsed light signal S travels at a 30 velocity vi. At a selected interval of time after the pulsed light signal S has been transmitted into one end 1A of the fiber 1 a ramped Raman pump signal RPS is transmitted into said end 1A of the fiber. The WO 2006/003206 PCT/EP2005/053218 -6 wavelength of the pulsed light signal S may typically be between 15 and 16 pn and the wavelength of the Raman pump signal RPS may typically be between 14 and 15 pW. As a result of its lower wavelength the Raman pump signal RPS 5 travels faster, at a velocity v2 > vl through the fiber 1 than the pulsed light signal S and therefore the Raman pump signal RPS reaches the pulsed light signal S at a distance dl from the first end 1A of the fiber. In accordance with the invention the Raman pump 10 signal RPS is ramped, such that along the length of the ramped part RPSR the strength of the Raman pump signal RPS increases from RPSmin to RPSmax Thus, when the Raman pump signal RPS reaches the pulsed light signal S at a distance di from the first end 15 1A of the fiber 1 the Raman pump signal RPS only has its minimum strength RPSmin and the relatively strong light signal Si is only amplified minimally, which is illustrated as A 1 =Si + RPSmin The Raman pump signal will from this point on 20 continuously amplify the signal Si in a substantially linear manner equal to the fiber losses distributed along the length of the fiber. At a distance d 2 the pulsed light signal has been maintained in strength and the Raman pump signal RPS has 25 been weakened due to fiber losses and pump to signal energy transfer. The Raman pump signal will have a strength such that the resulting signal gain is equal to the fiber loss. The use of a ramped Raman pump signal RPS keeps the 30 signal level below the Stimulated Brillouin Scattering (SBS) threshold in the region between di and d 2 such that the dynamic range and reach is increased of a fiber WO 2006/003206 PCT/EP2005/053218 -7 optical sensing system, such as an ODTR-system, in which the fiber 1 is employed as a fiber optical sensor.
Claims (11)
1. A method for amplifying a light pulse in an optical fiber, wherein a Raman pump signal having a lower wavelength than the light pulse is transmitted at a selected interval of time after the light pulse into the 5 optical fiber, with dispersion such that the Raman pump signal travels faster through the fiber than the light pulse and reaches and enhances the light pulse after the light pulse has travelled along a selected distance through the fiber, wherein the Raman pump signal is 10 ramped in a substantially linear manner such that the cumulative amplification increases with the distance along which the light pulse has travelled along the length of the fiber and such that the Raman gain is substantially similar to the fiber losses of the 15 amplified signal.
2. The method of claim 1, wherein the wavelength of the Raman pump signal is between 50 and 250 nm lower than the wavelength of the light pulse and the Raman pump signal (RPS) increases in a substantially linear manner from 20 Al= Sl+RPSmin at a distance disto A 2 =S+ RPSmax at a distance d 2 >di from the point where the light pulse is transmitted into the optical fiber.
3. The method of claim 2, wherein the wavelength of the light pulse is between 1400 and 1700 nm. 25
4. The method of claim 1, wherein the Raman pump signal is transmitted at such an interval of time after the light pulse and has such a lower wavelength than the light pulse that the Raman pump signal reaches the light pulse at a point in the optical fiber which is located at WO 2006/003206 PCT/EP2005/053218 -9 a distance between 1 and 10 Kilometers from the point where the light pulse and Raman pump signal have been transmitted into the optical fiber.
5. The method of claim 1, wherein the Raman pump signal 5 is ramped such that full gain of the light pulse by the Raman pump signal is accomplished at a distance of between 1 and 100 Kilometers from the point where the Raman pump signal has reached the light pulse.
6. The method of claim 1, wherein the Raman pump signal 10 contains multiple Raman pumping wavelengths and is used to amplify both the light pulse and the part of the Raman pump signal that amplify the light pulse as they propagate down the fiber.
7. The method of claim 6, wherein the different 15 wavelengths of the Raman pump signal travel at different speed and overlap at different times/locations.
8. The method of claim 7, wherein the spacing between the different pump sources is from 30 nm to 200 nm.
9. A system for amplifying a light pulse in an optical 20 fiber, the system comprising a Raman pump signal transmitter for transmitting a Raman pump signal having a lower wavelength than the light pulse at a selected interval of time after the light pulse into the optical fiber, such that the Raman pump signal travels faster 25 through the fiber than the light pulse and reaches and enhances the light pulse after the light pulse has travelled along a selected distance through the fiber, wherein the Raman pump signal is ramped such that the amplification increases with the distance along which the 30 light pulse has travelled along the length of the fiber.
10. The system of claim 9, wherein the system is configured for use to extend the reach of pulsed systems where the travel time reflects position along a fiber. WO 2006/003206 PCT/EP2005/053218 - 10
11. The system of claim 9, wherein the pulsed system is a pulsed sensing system, such as an Optical Time Domain Reflectometry (ODTR) system based on Rayleigh backscattering, a Strain and/or Temperature sensing 5 system based on Brillouin backsc-attering, a temperature sensing system based on Raman backscattering, an interferometric Fabry-Perot type sensing system, and/or a direct wavelength detection system based on Fiber Bragg Gratings (FBGs).
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP04103182 | 2004-07-06 | ||
| EP04103182.4 | 2004-07-06 | ||
| PCT/EP2005/053218 WO2006003206A1 (en) | 2004-07-06 | 2005-07-06 | Light pulse amplification in long optical fibers |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| AU2005259160A1 true AU2005259160A1 (en) | 2006-01-12 |
Family
ID=34929294
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU2005259160A Abandoned AU2005259160A1 (en) | 2004-07-06 | 2005-07-06 | Light pulse amplification in long optical fibers |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US20070273961A1 (en) |
| CN (1) | CN1981412A (en) |
| AU (1) | AU2005259160A1 (en) |
| BR (1) | BRPI0513038A (en) |
| CA (1) | CA2571453A1 (en) |
| GB (1) | GB2430094A (en) |
| WO (1) | WO2006003206A1 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB0614991D0 (en) * | 2006-07-28 | 2006-09-06 | Schlumberger Holdings | Improvements to raman amplification in distributed sensors |
| ES2388629B1 (en) * | 2009-05-22 | 2013-08-27 | Consejo Superior De Investigaciones Científicas (Csic) | SYSTEM FOR IMPROVING THE DYNAMIC RANGE AND REDUCTION OF THE UNCERTAINTY OF MEASUREMENT IN DISTRIBUTED SENSORS ON OPTICAL FIBER. |
| CN102410887B (en) * | 2011-09-01 | 2013-06-19 | 北京航天时代光电科技有限公司 | Stimulated Raman scattering (SRS) compensation method in distributed optical fiber temperature sensor system |
| IL254803B2 (en) | 2017-09-29 | 2023-09-01 | Prisma Photonics Ltd | Tailor distributed amplification for fiber sensing |
| CN111162834B (en) * | 2018-11-07 | 2021-11-02 | 中国移动通信集团湖南有限公司 | Optical time domain reflectometer test method and optical time domain reflectometer |
| US11624681B2 (en) * | 2020-01-16 | 2023-04-11 | Saudi Arabian Oil Company | Overcoming OTDR dead zones using a few-mode fiber |
| US20210318182A1 (en) * | 2020-04-13 | 2021-10-14 | Nec Laboratories America, Inc | Distributed fiber optic sensing of temperature using a polarization scrambler |
| CN116086645B (en) * | 2023-04-10 | 2023-06-27 | 山东省科学院激光研究所 | Temperature measurement method applied to optical fiber Raman distributed system |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3577236D1 (en) * | 1984-12-13 | 1990-05-23 | Stc Plc | OPTICAL AMPLIFIER. |
| JPH02281122A (en) * | 1989-04-24 | 1990-11-16 | Nippon Telegr & Teleph Corp <Ntt> | Apparatus for measuring dispersion and distribution of wavelength of optical fiber |
| US5880866A (en) * | 1996-11-13 | 1999-03-09 | At&T Corp | Time division demultiplexing using selective Raman amplification |
| US6101024A (en) * | 1998-03-24 | 2000-08-08 | Xtera Communications, Inc. | Nonlinear fiber amplifiers used for a 1430-1530nm low-loss window in optical fibers |
| CA2414951C (en) * | 2000-07-10 | 2010-09-21 | Mpb Technologies Inc. | Cascaded pumping system and method for producing distributed raman amplification in optical fiber telecommunication systems |
| US6700696B2 (en) * | 2000-08-09 | 2004-03-02 | Jds Uniphase Corporation | High order fiber Raman amplifiers |
| JP2003115799A (en) * | 2001-10-03 | 2003-04-18 | Fujitsu Ltd | Optical transmitter and stimulation control method |
-
2005
- 2005-07-06 AU AU2005259160A patent/AU2005259160A1/en not_active Abandoned
- 2005-07-06 BR BRPI0513038-7A patent/BRPI0513038A/en not_active IP Right Cessation
- 2005-07-06 GB GB0625204A patent/GB2430094A/en not_active Withdrawn
- 2005-07-06 CN CN200580022862.3A patent/CN1981412A/en active Pending
- 2005-07-06 CA CA002571453A patent/CA2571453A1/en not_active Abandoned
- 2005-07-06 WO PCT/EP2005/053218 patent/WO2006003206A1/en not_active Ceased
- 2005-07-06 US US11/631,758 patent/US20070273961A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| GB0625204D0 (en) | 2007-01-24 |
| CN1981412A (en) | 2007-06-13 |
| GB2430094A (en) | 2007-03-14 |
| WO2006003206A1 (en) | 2006-01-12 |
| CA2571453A1 (en) | 2006-01-12 |
| BRPI0513038A (en) | 2008-04-22 |
| US20070273961A1 (en) | 2007-11-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MK5 | Application lapsed section 142(2)(e) - patent request and compl. specification not accepted |